1. Technical Field
The present invention is directed generally toward integrated circuit inductors. More particularly, the present invention relates to a method and apparatus for passivating inductively coupled surface currents.
2. Description of the Related Art
Integrated circuit (IC) inductors are inductive coils that are formed above a semiconductor device. IC inductors cause concern with inductively coupled substrate surface currents. Such currents lessen the quality factor (Q) for a device and can cause latch-up and other failures on a chip. The “Q” of a device, in this case, is a measure of how good the inductor is. If surface currents caused by an inductor are detrimental to an IC device, then the “Q” will be unacceptable.
One solution to inductively coupled surface currents is to include floating poly and metal sheets underneath the inductor. The results of floating metal/poly sheets are unknown at this time. Another solution is to use ion implantation and no subsequent annealing over a silicon-on-insulator (SOI) layer to mitigate this effect. SOI is an expensive process and, thus, may be considered disadvantageous for that reason alone.